Apple CEO Tim Cook started the unusual public criticism in late March. During a joint interview with Recode and MSNBC, he was asked what he would do about the crisis if he were in Facebook CEO Mark Zuckerberg's position.

"I wouldn't be in the situation," said Cook.

He added that Apple reviews apps to confirm that each one meets the privacy standards his company has required for users.

"We don't subscribe to the view that you have to let everybody in that wants to, or if you don't, you don't believe in free speech," said Cook. "We don't believe that."

Cook also questioned the practice of social media platforms monetizing the personal data of their users.

"If you want to build a service which is not just serving rich people, then you need to have something that people can afford," said Zuckerberg.

Championing his own company's business model, Zuckerberg also said: "At Facebook, we are squarely in the camp of the companies that work hard to charge you less and provide a free service that everyone can use. I don’t think at all that that means that we don’t care about people."

Zuckerberg is scheduled to testify before congressional committees in Washington this week about the Cambridge Analytica episode and Facebook's response.